Context. It has been decades since the circadian variation of the secretion of the thyroid stimulating hormone (TSH) was proven in humans. Even so, there are few studies on human beings that explored the relationship existing between night shift circadian rhythm deregulation and thyroid disorders.
Methods. We have revised the occupational medicine files of all employees in a single speciality hospital to conduct an observational study on the prevalence of thyroid disorders in night shift compared to day shift workers. Age, gender, occupational history, body mass index and specialist diagnosed thyroid disorders were recorded. Numerical variables were compared with ANOVA test, and categorical ones with chi test (StatPlus for Mac version v6).
Results. Obesity was slightly more prevalent in night shift workers, but not statistically significant. Instead, we found a significant increase in the prevalence of thyroid disorders in night shift workers (X= 7.424, p = 0.006). As this is a mere observational study, our results only contribute to the pool of data concerning the relationship between thyroid dysfunction and night shifts.
Conclusions: These results should raise awareness, particularly among occupational physicians and endocrinologists, about the influence of sleep and circadian rhythm deregulation on the raising incidence of thyroid disorders.
Marina Ruxandra Oțelea, Anca Streinu-Cercel, Daniela Manolache, Andreea Mutu, Lavinia Călugăreanu, Dana Mateș and Oana Săndulescu
In many large cohort studies, the night shift constitutes a risk factor for developing cardiovascular disease and diabetes in workers. Current screening tests for people working in night shift include fasting glycaemia and electrocardiography. In fact, there are few studies focused on the description of the electrocardiographic changes after the night shift. This article describes the protocol of the “ECG modifications induced by the disturbance of the circadian rhythm in night-shift workers (ECGNoct)” study, which was initiated by the National Institute for Infectious Diseases “Prof. Dr. Matei Balș”. Nurses represent the target population.
The protocol includes a full medical and occupational history, lifestyle habits (smoking, alcohol, nutrition), anthropometric and blood pressure measurements, blood tests (fasting glycemia, total cholesterol, triglycerides and high density lipoprotein cholesterol) and electrocardiogram recording. For nurses working in (night) shifts, we will record the electrocardiogram before and soon after the night shift. A cross sectional study will analyze the incidence of the metabolic syndrome criteria, the cardio-metabolic diseases and the electrocardiographic modifications and will compare the results between the group of nurses working and the group of nurse who do not. Based on these results, a longitudinal study will test the hypothesis that night shift increases the risk for cardio-metabolic diseases and that the electrocardiographic modifications precede the clinical symptoms. The results of the study will provide data on the association of night shifts and other non-occupational risk factors with the cardio-metabolic diseases in this specific population of healthcare workers that potentially will integrate into the occupational medicine policies.